This invention relates to a decorated shaped product, a method for manufacturing the same and a shaped base material therefor, and more particularly to a shaped base material, a decorated shaped product obtained by forming a source pattern on the shaped base material and a method for manufacturing such a decorated shaped product.
The words "shaped base material" used herein indicate a shaped material obtained by subjecting a molding material to injection molding or the like. The words "decorated shaped product" used herein mean a product obtained by forming a source pattern on the shaped base material. Thus, it will be noted that the shaped base material corresponds to an intermediate product for the decorated shaped product which is a final product. The words "source material" used herein mean a material which includes a natural material such as wood, an ore or the like and on which a decoration of the decorated shaped product of the present invention is based. The words "source pattern" used herein mean a pattern of the source material such as, for example, a woodgrain pattern, a marble pattern or the like. Formation of the source pattern on the shaped base material may be carried out by, for example, transfer such as printing, coating, or the like. The words "source expression" or "source design" mean a motif, expression or design of the source material including the source pattern and the like.
Formation of a shaped base material by injection molding or the like has been often carried out by foaming a molding material in order to decrease the weight of the shaped base material and improve physical properties thereof. Unfortunately, such foaming often causes a streak-like flow pattern called a silver streak to occur on a shaped base material obtained. The shaped base material having such a flow pattern formed thereon is generally recognized to be defective. In order to remedy such a defect, it has been carried out to apply a base coat of a deep color to the defective shaped base material or apply a design or color sufficient to keep the defect from sight or to thereby prepare a desired transfer pattern which is then printed or coated.
There have been employed curved-surface printing techniques for printing a design such as a source pattern or the like on a shaped base material having a complicated curved surface and/or a plane surface continuously formed thereon. The curved-surface printing techniques use a transfer film including a carrier sheet previously coated thereon with a transfer pattern such as a source pattern or the like, wherein the transfer pattern is transferred onto a surface of the shaped base material utilizing a liquid pressure generated by immersing the shaped base material by a predetermined depth in a transfer liquid while floating the transfer film on the transfer liquid.
The curved-surface printing techniques are considered to be epoch-making, because of successively accomplishing transfer of a source pattern to a shaped base material which conventional coating techniques fail to successively carry out. Nevertheless, the techniques fail to satisfy recent demands relating to formation of an expression or design more closely resembling that of a source material.
In view of the foregoing, a printed product by liquid-pressure transfer and a method for manufacturing the same have been proposed as disclosed in Japanese Patent Application Laid-Open Publication No. 166300/1994. In the proposal, two transfer layers different in transfer pattern are used to satisfactorily express depth which the conventional curved-surface printing techniques fail to provide. Unfortunately, the proposal is deficient in productive efficiency because it is necessary to repeat the transfer operation.
Also, an attempt has been made for improving a shaped base material so that it per se may contribute to an improvement in source expression or design. The attempt is to add woodmeal to a synthetic resin material which is a molding material, in order to provide a shaped base material with a tone, a smell and a touch closely resembling those of wood. However, wood generally possesses peculiar patterns such as a flat grain pattern, a pattern called a grain (grain pattern) wherein medullary rays complicatedly cross with each other, and the like; therefore, mere addition of the woodmeal to the synthetic resin material fails to permit such patterns to be expressed.
Another attempt has been carried out to express a flat grain pattern by adding a color pigment to a synthetic resin material to prepare a mixture, followed by shaping of the mixture by extrusion, to thereby provide a pattern resembling a flat grain pattern. However, an actual flat grain pattern is delicately varied in color and tone such as gloss, shade or the like. Thus, mere mixing of the color pigment with the synthetic resin material fails to permit delicate variations in color and tone to be expressed.
Further, it has been proposed to mix a color pigment with a synthetic resin material to prepare a mixture, which is then subjected to injection molding to provide a flat grain pattern similar to that obtained by the above-described extrusion or a different source pattern. However, such proposal likewise fails to provide a source pattern resembling that of an actual source material, so that it is still desired to take an approach necessary to provide the mixture with any directionality or uneven streak. Moreover, there has been made an attempt to improve coating techniques to provide any further source expression or decorative expression while utilizing the above-described shaped base material. Nevertheless, no satisfactory results were obtained.